1. Field of the Invention
The present invention provides an improvement on China Patent Utility No. ZL 03 2 03726.0, entitled “Rack for LCD Monitor”.
2. Description of the Related Art
FIGS. 1 and 2 show a rack for LCD monitor according to China Patent Utility No. ZL 03 2 03726.0. This rack is adapted to support a LCD monitor or LCD TV, allowing adjustment of the elevation and angle of the LCD monitor or LCD TV. According to this design, the rack comprises a base (10′), which has a horizontally extended area that can be positioned on a flat surface positively, an upright tube (11′) vertically upwardly extended from the base (10′) at the top, a telescopic arm (12′) inserted into the upright tube (11′), a resilient means (13′) that imparts an upward force to the telescopic arm (12′) relative to the upright tube (11′), a holder frame (20′) fixedly provided at the free end of the telescopic arm (12′), a first steering member (21′) pivotally connected to the holder frame (20′) by a Z-axis pivot, a second steering member (22′) pivotally connected to the holder frame (20′) by a pair of X-X axis pivot and turnable in direction perpendicular to the first steering member (21′), and a third steering member (23′) pivotally connected to the front side of the second steering member (22′) by a Y-axis pivot and adapted to bearing the load and freely rotatable relative to the second steering member (22′). In FIG. 1, the resilient means (13′) is an air cylinder (13′) provided within a space at the center of said telescopic arm (12′), having a cylindrical casing (131′) with its one end connected to the free end of the telescopic arm (12′), a piston (133′) axially movably supported in the cylindrical casing (131′), and a piston rod (132′) for driving the piston (133′) being fixedly fastened to the base (10′). When the telescopic arm (12′) is lowered, the air cylinder (13′) imparts a resisting force to the telescopic arm (12′). According to this design, the capacity of the air cylinder (13′) is determined in such a way that the resisting force of the air cylinder (13′) is slightly larger than the load at the third steering member (23′), and the pressure difference between the resisting force of the air cylinder (13′) and the load is set up by the friction force between the telescopic arm (12′) and the upright tube (11′). Therefore, the telescopic arm (12′) can be freely moved up and down relative to the upright tube (11′) and then positioned in the desired position. According to the embodiment shown in FIG. 2, the resilient means (13′) is a spring (13″) which achieves the same effect.